There has conventionally been known a technology of etching a processing target by using an amorphous carbon film as an etching mask. For example, Patent Document 1 discloses a method of etching an amorphous carbon film using a resist layer as a mask, transferring a predetermined pattern to the amorphous carbon film, and using the amorphous carbon film as a mask of the processing target. The etching mask of such an amorphous carbon film is used for forming a stepped structure on a multilayered film in which an insulating film and a conductive film are laminated alternately in a manufacturing process of, for example, an NAND type flash memory (see, e.g., Patent Document 2).